Patent Document 1 discloses the configuration of a light-emitting element that is high in emission intensity, and furthermore able to achieve emission wavelengths with a narrow full width at half maximum by arranging, to a light-emitting layer, quantum dots with rare earth atoms attached to a surface of the quantum dots. The methods for producing and arranging quantum dots, which are disclosed in Patent Document 1, are as follows.
As for the method for producing quantum dots, first, a porous silicon semiconductor substrate obtained by anodization is subjected to ultrasonic treatment. As a result, quantum dots of silicon are eliminated from the porous silicon semiconductor, and dispersed in a solvent. Then, the quantum dots dispersed in the solvent are sorted for each size with the use of a centrifuge to obtain quantum dots of silicon in almost the same particle size.
Next, as for the method for arranging quantum dots, a silicon alkoxide is hydrolyzed by mixing the quantum dots and the silicon alkoxide, and then adding thereto an alkali or an acid as a catalyst. In this way, a sol-like or gel-like product can be obtained. Next, the obtained product is attached to a substrate by screen printing, and further subjected to annealing treatment to arrange the quantum dots in a kind of dispersion state.
Patent Document 1: Japanese Patent Application Laid-Open No. 2008-198614